Within the last 25 years, self-tapping screws have become the most
relevant fasteners in contemporary timber engineering. Restricting the
scope to their axial loading, the present thesis aims on gaining a
fundamental knowledge concerning the specifics of this kind of
dowel-type fastener. The related considerations are divided into the two
main topics, namely the (steel) product “self-tapping screw” itself and
the withdrawal behaviour, defined as the axial composite interaction
with the timber material where it is inserted into.With regard to
the product performance, the main outcomes are the derivation and
verification of a mechanical approach, describing the relationships of
its relevant design properties in dependence of a geometrically varying
thread profile, as well as some fundamental findings in terms of
fatigue-relevant loading and hydrogen-induced stress corrosion cracking
(HISCC).In case of the withdrawal behaviour, based on about 14,000
experimental results, the impact of several influencing parameters is
determined, discussed and described by means of empirical, stochastic
and mechanical modelling. Parameters, where a significant influence was
found, are finally included in the determination of a universal approach
for the prediction of the screw’s mean and characteristic withdrawal
strength, irrespective the timber product used and the position the
screw is inserted into.

Produktbeschreibung

Within the last 25 years, self-tapping screws have become the most
relevant fasteners in contemporary timber engineering. Restricting the
scope to their axial loading, the present thesis aims on gaining a
fundamental knowledge concerning the specifics of this kind of
dowel-type fastener. The related considerations are divided into the two
main topics, namely the (steel) product “self-tapping screw” itself and
the withdrawal behaviour, defined as the axial composite interaction
with the timber material where it is inserted into.With regard to
the product performance, the main outcomes are the derivation and
verification of a mechanical approach, describing the relationships of
its relevant design properties in dependence of a geometrically varying
thread profile, as well as some fundamental findings in terms of
fatigue-relevant loading and hydrogen-induced stress corrosion cracking
(HISCC).In case of the withdrawal behaviour, based on about 14,000
experimental results, the impact of several influencing parameters is
determined, discussed and described by means of empirical, stochastic
and mechanical modelling. Parameters, where a significant influence was
found, are finally included in the determination of a universal approach
for the prediction of the screw’s mean and characteristic withdrawal
strength, irrespective the timber product used and the position the
screw is inserted into.